<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      span {
        background-color: red;
        font-size: 16px;
      }
    </style>
  </head>
  <body>
    <!-- 这里因为出现了空白 -->
    <div> 
      <span>123</span>
      <span>234</span>
    </div>

    <div style="font-size: 0px"> 
      <span>123</span>
      <span>234</span>
    </div>

  </body>
</html>
